Lightroom Export to JPEG weirdness

I took a moonrise picture that was exposed for the moon, so I had to bump up the shadows. This resulted in noise which I then removed using the noise reduction controls. However, when I downsized and converted to jpeg using the Export function, the result was incredibly noisy, even though the sharpening box was not checked.

I then used Edit in Photoshop (CS5) where I resized and "Saved As" jpeg and the result matched my screen.

So why is the LR conversion so bad?

Below are the results of the LR5 export followed by the Photoshop jpeg. Double click on the pictures to really see the difference. Note that the Photoshop result matches my LR screen.